SOIUMDiE— TAMIAS ASIATIC DS AND VA1UET1ES. 795 



America southward nearly to the United States, decreasing in size and 

 becoming brighter in color southward, in the interior, and thus passing grad- 

 ually into var. quadrivittatus. 



Var. QUADRIVITTATUS. 



Rocky Mountain Chipmunk. 



Varietal chars. — Length of head and body 4.50 to 5.00 ; of tail to end 

 of vertebra? about 3.50 ; to end of hairs about 4.50. Pattern of coloration 

 strictly the same as in var. borealis, but the colors brighter, with much more 

 rufous, and the size smaller. Under parts sometimes faintly tinged with fulvous. 

 The black dorsal stripes are edged and more or less mixed with rufous; the 

 light stripes, particularly the outer, are whiter, varying from grayish-white to 

 pure white ; the sides of the body, especially anteriorly, are bright reddish- 

 ferrugineous ; the tail yellowish-rusty, with a subterminal border of black 

 edged with yellowish. 



Habitat. — Middle and southern portions of the Rocky Mountains, from 

 near the northern boundary of the United States to New Mexico. Also in 

 the mountain-ranges, thence westward to the Pacific coast, and in the Black 

 Hills. Most specialized in the mountains of Colorado. Passes insensibly, at 

 the northward, into var. borealis; at the eastward and in the Great Basin, 

 into var. pallidum in Northern California and Oregon and in the Bitter Root 

 and Cascade Ranges, into var. townsendi. 



Var. PALLIDUS. 

 Pale Chipmunk. 



Varietal chars. — Smaller and paler than var. quadrivittatus. Length 

 of head and body 4.25 ; of tail to end of vertebrae 3.25 ; to end of hairs 4.00 

 to 4.25. General color above pale whitish-gray, the sides slightly washed 

 with pale fulvous. The dark dorsal stripes are dusky, faded reddish-brown; 

 outer pair of light stripes nearly white, inner grayish-white ; generally only 

 the middle dark stripe decidedly blackish. Yellow of the tail very pale 

 clay-color. 



Habitat. — The dry plains of the Upper Missouri and Yellowstone and 

 the desert plains of the Great Basin. Everywhere passing into var. quadri- 

 vittatus at the edges of the wooded mountain-ranges, of which it is merely a 

 depauperate pallid form. The prevalent form over the plains of the Yellow- 



